Many industrial applications generate wastewater that is contaminated with undesirable or hazardous fluid materials, such as oil. These operations include oil drilling, mining and natural gas fracking. Also, spills from oil rigs into seawater generate emulsified oil in the water that is difficult to separate. The use of methods such as hydrocyclones, absorptive media, mechanical filtration, and chemical dispersion to separate the oil from the water are both cost prohibitive and possibly injurious to the environment.
Acoustophoresis is the separation of particles using high intensity sound waves. It has long been known that high intensity standing waves of sound can exert forces on particles. A standing wave has a pressure profile which appears to “stand” still in time. The pressure profile in a standing wave varies from areas of high pressure (nodes) to areas of low pressure (anti-nodes). Standing waves are produced in acoustic resonators. Common examples of acoustic resonators include many musical wind instruments such as organ pipes, flutes, clarinets, and horns.
It would be desirable to provide more effective methods of separating emulsified oil and other contaminants from the contaminated water at reduced cost and low environmental impact.